Liquid level and temperature apparatus



June 24, 1958 s. E. JACKE LIQUID LEVEL AND TEMPERATURE APPARATUS Filed Sept. 28, 1955 IN V EN TOR.

United States Patent LIQUID LEVEL AND TEMPERATURE APPARATUS Stanley E. Jacke, Walled Lake, Mich., assignor to Detrex Chemical Industries, Inc., a corporation of Michigan Application September 28, 1955, Serial No. 537,103

4 Claims. (Cl. 310-81) This invention relates to improvements in apparatus for treating a work object. It is concerned with apparatus for cleaning and degreasing intricately formed metal parts through the combined application of chlorinated hydrocarbon solvents and ultrasonic energy. More particularly, this invention relates to control of cleaning apparatus through control of temperature and liquid level.

The ultrasonic well of present day ultrasonic cleaning and degree-sing apparatus contains a chlorinated hydrocarbon solvent having ultrasonic transducers submerged therein. The liquid in the ultrasonic well performs several functions besides its principal one of acting as a cleaning agent. One of these functions is to cool the curved or fiat transducers .since these elements are destroyed by excessive heat. If electrical energy is applied to these transducers when they are not submerged in and cooled bya liquid they are destroyed quite rapidly.

The present method of avoiding such destruction of the transducers when not submerged in liquid is to provide the ultrasonic well with a float switch which opens the generator circuit when the liquid level drops below the transducers. Float switches are comparatively expensive. Further, they have moving parts which fail to function properly when soil cleaned from the work object is deposited thereon. 'Even' though the transducers remain submerged in the liquid they still overheat and are destroyed whenever the liquid temperature becomes excessive for any reason, such as lack of cooling water, clogged filter, closed valve or other improper operation of the ultrasonic cleaning machine.

Accordingly, it is an object of this invention to provide means for preventing the energizing of the transducers when the transducers are not submerged in a liquid. Au other object is to provide means for preventing the energizing of the transducers when the temperature of the liquid is too hot. A further object of this invention is to provide means for preventing the energizing of the transducers until the zone above the surface of the liquid becomes hot enough.

Other objects and advantages of the invention, including 7,

the simplicity and economy of the same, will be understood from the detailed description to follow, throughout which reference is made to the accompanying drawing which represents a view in front elevation of cleaning apparatus including liquid level'and temperature apparatus constructed in accordance with the invention.

Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer to the structures shown in the drawing only, and are not intended to define or limit the scope of the invention. 1

Turning now to the drawing and the specific form of the invention selected for illustration therein, the number 11 designates a housing which may be of sheet metal. Hous ing 11 contains an ultrasonic well 12 which is defined by left wall 13, slanted bottom 14, right wall 15, front wall .16 and the back wall of housing 11. Right wall 15 is part into the vapor zone above well 12.

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of an overflow dam 17 which separates ultrasonic well 12 from another well 18.

A liquid, preferably a chlorinated hydrocarbon liquid such as trichlorethylene, is contained within ultrasonic well 12 and normally maintained at level L1. Supported in the well 12 and submerged in the liquid are ultrasonic transducers 21. Vapors are generated in a boiling well located elsewhere in the apparatus (not shown) within housing 11. These vapors are condensed by a cooling jacket 22 which completely surrounds housing 11 at a level above the surface of the liquid.

A generator 23 is provided which supplies power to energize transducer 21. Generator 23 is connected to transducers 21 by conductors 24. Reference is hereby made to U. S. Patent No. 2,771,086 of Thomas I. Kearney, issued November 20, 1956, which fully describes cleaning apparatus of the type to which the present invention relates.

Mounted on wall 16 of enclosure 11 above the level L1 of the liquid in well 12, is a thermostatic switch 25, which may be of bulb or bi-metal types. Switch 25 has a temperature sensitive element extending within enclosure 11 A similar thermostatic switch 26 is mounted on wall 16 of housing 11 with its temperature sensitive element extending within well 12 below the surface L1 of the liquid and above the level of the transducers 21. Switch 25 is provided with an armature 27 and a contact 28, armature 27 having a conductor 29 leading back to generator 23 and contact 28 having a' conductor 31 leading to a contact 32 of switch 26. Contact 32 has associated with it an armature 33 which is con- Y nected with generator 23 by a conductor 34. a

The operation of this invention will now become apparent. Using trichlorethylene as the liquid within well 12, the top thermostatic switch 25 would be set to close when the temperature of the vapor within housing 11 above the surface L1 of the trichlorethylene reaches approximately 180 F. The lower thermostatic switch 26 is normally closed but is set to open when the temperature reaches approximately F. When either switch 25 or 26 are open, and when both are open, generator 23 does not operate and no electrical energy is supplied to transducers 21.

Top thermostatic switch 25 opens to shut down generator 23 when no vapors are generated within enclosure 11. Switch 25 closes and energizes the electric generator circuit only when the temperature above liquid level L1 has reached the operating temperature of the machine. This is about F. when trichlorethylene is the solvent.

Lower thermostatic switch 26 opens to shut down generator 23 when the level of the solvent falls below the sensitive element of thermostatic switch 26 so that it is no longer submerged in the solvent. Lower thermostatic switch 26 also opens to shut down generator 23 even though the level of the solvent is above the sensitive element of thermostatic switch 26 whenever the temperature of the solvent is too hot. Excessive temperature acts upon the sensitive element of thermostatic switch 26 to open it and shut down generator 23 whether the excessive temperature is from the vapors when the level of the solvent falls below the sensitive element of thermostatic switch 26, or whether, the liquid level being above that sensitive element, the temperature of the solvent itself is too hot. Thermostatic switch 26 protects transducers 21 for overheating and switch 26 is positioned above transducers 21 so that as the solvent level falls, generator 23 shuts down before the solvent level falls below the level of transducers 21. When the liquid level is falling thermostatic switch 26 shuts down generator 23 before transducers 21 emerge from the solvent.

Thermostatic switch 26 also opens when, for any reason such as lack of cooling water, a clogged filter, a

about 160 F. where trichlorethylene is the liquid used in' well 12.

. While I have disclosed a preferred embodiment of this invention, it will 'be understood that various modifications may be made including the use of equivalent means, re-' versal of parts, and the useof certain features independently of the use of others, all within the spirit and scope of this invention as set forth in the appended claims.

Having thus described my invention, I claim: 1..I'n' a Well containing a chlorinated hydrocarbon liquid with an ultrasonic transducer submerged therein and with a vapor Z0116 located above the surface of said liquid, an electrical generator and an electrical'circuit connecting said transducer and generator, a liquid level and temperature'control apparatus to protect said transducer from excessive heat, said apparatus comprising an upper thermostatic switch positioned in the well above the surface of the liquid and connected in said circuit, said upper switch being arranged to close when the temperature of said'vapor zone reaches a predetermined value and to open when said temperature falls below said predetermined value, and a lower thermostatic switch submerged in the liquid and positioned above the ultrasonic transducer, said lower switch being connected in said circuit, said lower switch being arranged to open when the liquid temperature exceeds a predetermined value and to close when said temperature falls below said predetermined value, said lower switch being arranged to open when said liquid is below a predetermined level between the lower switch and said transducer and said lower switch is contacted by said vapor at a temperature above a predetermined value;

2. The apparatus defined in claim 1, said switches being connected in a series circuit.

' 3. Liquid level and temperature control apparatus comprising a well, a chlorinated hydrocarbon liquid contained within said well with a vapor zone located above the surface of the liquid, an ultrasonic transducer submerged in said liquid, a generator of electricity, conductor means connecting said generator to said transducer, a first thermostatic switch means positioned in the a pump, the temperature of a means being arranged to close when the temperature of said vapor zone "reaches a predetermined value andto open when the temperature falls below said predetermined value, a second thermostatic switch means submerged in the liquid and positioned above said transducer, said secand switch means being arranged to open when the liquid temperature exceeds a predetermined value and to close when the liquid temperature falls below said predetermined value, said second switch means also opening when above the surface of the liquid and contacted by the vapor at a vapor temperature above a predetermined value with the'level of the liquid below a predetermined level between the second. switch means and said transducer, and an electrical circuit connecting both of said switch means with said transducer and said generator.

4. Liquid level and temperature apparatus for ultrasonic cleaning comprising a well; a cleaning liquid contained Within said well; an ultrasonic transducer submerged in said liquid; electrical means for energizing said "transducer; a vapor zone located in the well above the surface of said liquid for containing vapor of said liquid; an upper switch means located in the vapor zone of the well maintaining said transducer deenergized until the temperature of the vapor exceeds a predetermined value; and a lower switch means located in the well maintaining said transducer de-energized when the lower switch means is submerged in the liquid and the temperature of the liquid exceeds a predetermined value, and maintaining said transducer deenergized when the' lower switch means is above the surface of the liquid and the lower switch means is contacted by the vapor at a temperature above a predetermined value; said trans! ducer, electrical means for energizing said transducer, and upper and lower switch means being connected together in an electrical circuit.

' ReferenceslCitedin the file of this patent UNITED STATES PATENTS 976,748 Schmidt Nov. 22, 1910 2,257,997 Barnes Oct. 7, 1941 2,771,086 Kearney Nov. 20, 19 56 

